Male sexual victimization is more commonly examined in the context of child sexual abuse (CSA) rather than adult sexual assault (ASA). This qualitative study examines the meaning-making of ASA among men who have been sexually assaulted in adulthood (after age 18) by analyzing the ways they experience and narrate adult age and masculinity in this context. To gain a comprehensive understanding of male sexual victimization in adulthood, data were gathered through 40 in-depth interviews with 19 Israeli male ASA survivors and 21 sexual trauma therapists. This study found that survivors perceived the sexual assaults they experienced as adults through the dual lenses of adulthood and masculinity, which resulted in an identity where expectations of being an adult and being male became intertwined. This perspective deepened their sense of loneliness, driven by the belief that adult men should be self-reliant, and distinguished the meaning-making of ASA from that of CSA. In addition, ASA survivors negotiated the narrative of being an adult male survivor of sexual assault using three strategies: detachment from the experience, minimization of the experience, and hypersexuality. Accordingly, we conclude that the perception of the assault by ASA survivors is shaped by both their masculinity and their maturity.